The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A typical multi-speed automatic transmission uses a combination of torque transmitting devices, such as clutches or brakes, to achieve a plurality of forward and reverse gear or speed ratios as well as a Neutral and a Park. Selection of speed ratios is typically accomplished by a microprocessor transmission control module that employs various vehicle parameters, for example vehicle speed, and various driver input signals, for example accelerator pedal position, to select the appropriate speed ratios. The transmission then engages a combination of the torque transmitting devices to provide the desired speed ratios.
The launch of the automatic transmission, i.e., the transfer of torque from an engine or power source to the transmission at engine start-up, is typically accomplished by a traditional torque converter that transfers torque via fluid coupling or by a wet clutch. Dry friction clutches, which exist within a transmission for normal ratio changing purposes, may also serve as launch clutches under certain conditions. However, the need to efficiently package these dry friction clutches, as well as components of the transmission including input shafts and pump assemblies, remains constant. Therefore, there is a need in the art for transmission and powertrain architecture that maximizes performance and fuel efficiency while minimizing packaging space and weight.